New backstrap vagus electrode for continuous intraoperative neuromonitoring in thyroid surgery.

INTRODUCTION: Continuous intraoperative neuromonitoring (CIONM) via vagal nerve stimulation allows real-time surveillance of the recurrent laryngeal nerve during thyroid surgery. However, for effective CIONM, subtle changes in recurrent laryngeal nerve conductivity have to be detected. A newly developed stimulation electrode that provides stable nerve stimulation and safe application is presented. METHODS: For electrode validation, current distribution was simulated with the finite element method. Mechanical characteristics were assessed through bench testing. Clinical evaluation was initiated with 11 thyroid surgeries. RESULTS: Experimental and clinical results led to the development of a tripolar gold/polyimide electrode mounted onto a backstrap-shaped silicone body. It facilitated rapid electrode implantation and extraction (median implantation time 4 ± 19 seconds). Peak extraction force was 570 mN. Median supramaximal stimulation currents were 2.00 ± 0.95 mA and resulted in reliable electromyogram responses (median 3.1 ± 3.0 mV). No intraoperative electrode dislocations occurred, and no postoperative nerve palsy was observed. CONCLUSION: The new backstrap vagal stimulation electrode meets the requirements for reliable CIONM.

Sashimi NOTES--extraction of bulky specimens in no-scar operations.

A major obstacle in no-scar surgery is the extraction of large, bulky or rigid specimen. Thus, a method is needed that allows for extraction of large specimens without situs contamination in women and men. It should enable safe treatment of infectious or malignant disease while preserving pathologic workup. Five patients suffering from diverticulitis with expected bulky and rigid specimen were enrolled into this early series. Preparation was performed transumbilically in single-port technique. To prevent new scar formation, the incision was limited to the base of the umbilicus without extension onto the sound abdominal skin. A functionally and topologically extracorporeal compartment was created within the abdomen by introduction and insufflation of a tear-proof impermeable retrieval bag. The specimen was sliced in a controlled fashion inside the compartment along a pre-marked geometry. Controlled specimen dissection in a dedicated intraabdominal resection compartment was feasible. The dissected specimen could be retrieved through the 1.5 cm umbilical incision without spillage of material. The geometry of the extracted organ was reconstructed in detail allowing for uncompromised pathological workup. Extraction of bulky and rigid specimen is possible through natural orifices by the proposed controlled dissection method enabling the pathologist to reconstruct anatomical affiliation.

Snake charmer NOTES: a two-luminal access for hybrid NOS operations.

Despite recent advances in NOTES, NOS, SILS and related techniques, the feasibility of performing extensive surgery is still limited. Colon surgery usually requires additional access sites or complex technical means for triangulation and retraction. A method is presented that enables single-port colon surgery, supported by flexible colonoscopy. Single-port sigmoidectomy was performed in five cases on the porcine model. Flexible colonoscopy was used to manoeuvre the colon and expose its mesentery for dissection. The specimen was retrieved transrectally by invagination. Single-port sigmoidectomy supported by colonoscopy was feasible in all cases. The method provided a fixed framework, excellent organ guidance and exposition of the mesentery and enabled bowel-close mesocolic preparation. The access angle for preparation and visualisation could be altered during the procedure using the colonoscope. During autopsy on day 21, competent anastomotic healing with only rare interenteric adhesions was observed. One animal had a small preperitoneal abscess in the umbilical region while demonstrating completed skin healing. Flexible colonoscopy provided a fixed reference frame that enabled single-port preparation and dissection of the sigmoid colon. Under colonoscopic guidance, the access angle for dissection could be adapted according to the surgeon's needs. The procedures could be performed safely and effectively.

Artificial tactile feedback can significantly improve tissue examination through remote palpation.

BACKGROUND: In laparoscopy, impaired feedback information from the operation site and reduced instrument dexterity lead to high demands on surgeons' skill and experience. Pre-clinical studies have shown that artificial tactile feedback (ATF) could significantly improve the quality of tactile feedback information. Additional information about interaction effects of tissue features when using ATF as well as related detection thresholds would be valuable for drawing conclusions on possible clinical application scenarios. OBJECTIVE: To identify surgical procedures in laparoscopy that could benefit from ATF in tissue examination through remote palpation. METHODS: We have developed a laparoscopic grasper capable of providing ATF by measuring the pressure distribution on one forceps jaw with a tactile sensor array. The data was presented graphically on the endoscopic screen. We conducted a study among surgeons and non-surgeons, comparing the capability to detect hidden objects through remote palpation with and without ATF. The data were analyzed using repeated-measures multiple analysis of variance (MANOVA) in two designs. RESULTS: ATF could enhance feedback information with significant positive effects on accuracy, speed, the reduction of the number of grasps, and user confidence. The positive effect of ATF turned out to be especially strong if hidden objects were either hard and too small or large and too soft to be recognized by remote palpation without ATF. CONCLUSIONS: Our study contributes to the discussion on promising application scenarios of ATF-enhanced instrumentation in laparoscopic surgery. Based on our study results, such instrumentation may be valuable for detection and examination of hidden bodies or structures through remote palpation.

Implantable endoscopic gastric bypass - device and experimental procedure.

Malabsorptive bariatric surgery is an effective treatment option for morbid obesity, but may be associated with complications and side effects. We have developed a new experimental approach to creating a gastric bypass through an intraluminal access. The goal is to reduce postoperative complications and to reduce mid-term side-effects of malabsorptive bypass food passage and to allow easy reversion of the procedure. The new procedure is based on an implantable gastric bypass device, installed by combined transoral flexible and minimally invasive abdominal access. The newly developed device and procedure were studied in a pilot experimental trial in the porcine animal model (n=8). Endpoints were the feasibility of the technical procedure, the ability of the animal to eat and digest food, the implant functionality over the survival period and the absence of major complications over a short-term follow-up (one week). The procedure was technically successful in all eight animals. Animals were able to take in food and water till sacrifice. Four animals had major complications (one abdominal wall dehiscence, one invagination ileus of the small bowel, one dehiscence of the gastro-jejunal anastomosis and one myocardial infarction) and did not complete follow-up. In two cases migration of the device into the stomach was observed. The difference between our experimental technique and the gold standard surgical methods for gastric bypass consists of the endoluminal approach by implanting an intraluminal gastric bypass device. This concept avoids gastric transsection and an additional anastomosis and enables an adjustable food passage between the bypass and the natural duodenal passage. Further long-term follow-up studies are required.

Propeller-based wireless device for active capsular endoscopy in the gastric district.

An innovative approach to active locomotion for capsular endoscopy in the gastric district is reported in this paper. Taking advantage of the ingestion of 500 ml of transparent liquid by the patient, an effective distension of the stomach is safely achieved for a timeframe of approximately 30 minutes. Given such a scenario, an active swallowable capsule able to navigate inside the stomach thanks to a four propeller system has been developed. The capsule is 15 mm in diameter and 30 mm in length, and it is composed of a supporting shell containing a wireless microcontroller, a battery and four motors. The motors enable the rotation of propellers located in the rear side of the device, thus obtaining a reliable locomotion and steering of the capsule in all directions in a liquid. The power consumption has been properly optimized in order to achieve an operative lifetime consistent with the time of the diagnostic inspection of the gastric district, assumed to be no more than 30 minutes. The capsule can be easily remotely controlled by the endoscopist using a joystick together with a purposely developed graphical user interface. The capsule design, prototyping, in vitro, ex vivo and preliminary in vivo tests are described in this work.

Feasibility proof of a legged locomotion capsule for the GI tract.

BACKGROUND: A colonoscopy and a gastroscopy are the most important screening measures for malignant diseases in the GI tract. One of the main limitations is the lack of patient adherence to come in for a flexible endoscopy, especially in asymptomatic conditions. OBJECTIVE: The feasibility proof of a new generation of endoscopic capsules based on a novel propelling mechanism that features electromechanical legs. DESIGN: Teleoperated endoscopic 8-legged capsule. SETTING: Scuola Superiore Sant'Anna, Pisa, Italy, and novineon Healthcare Technology Partners GmbH, Tübingen, Germany. MAIN OUTCOME MEASUREMENTS: Successful locomotion in a lower-GI tract (LGI) phantom model and in a porcine colon. RESULTS: The testing session was organized into repetitive ex vivo trials and in vivo tests. The repetitive tests were performed for collecting reproducible data in various small series of individual experiments in standardized conditions, thus defining the best locomotion parameters. In vivo tests were performed in a porcine colon: the capsule, inserted transanally, traveled upward in the oral direction for 15 cm in about 5 minutes, against peristalsis. LIMITATIONS: The current version of the capsule travels curves by bouncing back from the wall and following step by step the direction of the curved bowel. Steering mechanisms are not yet implemented. CONCLUSIONS: This study shows the systematic development and medical assessment of an imaging capsule with self-propelling abilities. A full colonic passage was successfully demonstrated in the ex vivo phantom model. A net movement in in vivo tests has been achieved, thus giving a feasibility proof of the legged locomotion as a possible solution to the problem of self-locomoting endoscopic devices in the LGI.

Efficacy and morbidity of surgical therapy in late-stage encapsulating peritoneal sclerosis.

BACKGROUND: Encapsulating peritoneal sclerosis (EPS) is a rare but devastating complication of peritoneal dialysis composed of chronic abdominal pain, chronic ileus, and severe malnutrition. Operative therapy for EPS is a complex procedure, including perionectomy and enterolysis (PEEL). In contrast to simple adhesiolysis, PEEL comprises a restitution of intestinal passage and prevention of recurrent disease by decapsulation and partial deserosation. METHODS: We reviewed the treatment of patients with EPS at our referral center regarding perioperative morbidity, mortality, and long-term outcome. Only patients who underwent PEEL were included. Preoperative general status was ascertained by APACHE-II score and body mass index. Postoperative morbidity was stratified into minor and major complications. RESULTS: Between the years 2003 and 2010, 26 of 45 patients with late-stage EPS underwent PEEL. Median age was 54 years, APACHE-II score was 15, and body mass index was 21 kg/m². To achieve intestinal function, 9 bowel resections with immediate anastomoses were necessary. Eleven patients (37%) received a complete parietal peritonectomy. Overall morbidity was 44%, with minor complications in 2 patients (7%) and major complications in 11 patients (31%). Three patients (10%) died within the first year after operative treatment. CONCLUSION: PEEL is a treatment option that can be performed with low mortality and acceptable morbidity. It is a precondition that these patients are treated in specialized referral centers.

Auditory support for resection guidance in navigated liver surgery.

BACKGROUND: An alternative mode of interaction with navigation systems for open liver surgery was requested. Surgeons who use such systems are impeded by having to constantly switch between viewing the navigation system screen and the patient during an operation. METHODS: To this end, an auditory display system for open liver surgery is introduced with support for guiding the tracked instrument towards and remaining on a predefined resection line. To evaluate the method, a clinically orientated user study with 12 surgeons was conducted. RESULTS: It is shown in qualitative results from the user study that the proposed auditory display is recognized as a useful addition to the current visual mode of interaction. It was revealed in a statistical analysis that participants spent less time looking on the screen (10% vs. 96%). Accuracy for resection guidance was significantly improved when using auditory display as an additional information channel (0.6 vs. 1.4 mm); however, the overall time for the resection task was shorter without auditory display (47 vs. 24 s). CONCLUSIONS: By reducing dependence on the visual modality during resection guidance, the auditory display is well suited to become integrated in navigation systems for liver surgery.

Safety analysis of vagal nerve stimulation for continuous nerve monitoring during thyroid surgery.

OBJECTIVES/HYPOTHESIS: Intraoperative neuromonitoring (IONM) facilitates recurrent laryngeal nerve (RLN) identification, but various studies affirm virtually unchanged postoperative RLN palsy rates. Several authors meanwhile suggest continuous intraoperative neuromonitoring (CIONM) via vagal nerve stimulation (VNS) to improve RLN protection. However, knowledge of side effects of electrical VNS derives mainly from its therapeutic applications in the fields of neurology and psychiatry. The presented study was conducted to further evaluate the safety of CIONM and identify possible VNS related side effects. STUDY DESIGN: Prospective nonrandomized controlled trail. METHODS: Forty patients scheduled for thyroid or parathyroid surgery were enrolled in the trail. The intervention group consisted of 22 patients receiving VNS for CIONM. Eighteen patients were operated on with routine IONM. To assess VNS-induced effects on the autonomic nervous system (ANS), heart rate variability analysis (HRVA) was applied. Serum cytokine levels of tumor necrosis factor (TNF)-α were monitored to evaluate immunomodulatory effects of VNS. RESULTS: HRVA revealed significantly increased vagal activity during CIONM. This parasympathetic predominance was not countered by the sympathetic nervous system. Despite a significant increase of vagal tone, no hemodynamic events occurred; in fact, no significant changes in median heart rate or in median arterial blood pressure were detected. Even though anti-inflammatory effects of VNS have been reported, no attenuation of cytokine release of TNF-α was measured. CONCLUSIONS: VNS for CIONM resulted in increased vagal activity assessable via HRVA. The increased parasympathetic tone affected neither hemodynamics nor levels of the proinflammatory cytokine TNF-α. VNS for CIONM appears safe with the applied settings.

Impact of continuous intraoperative neuromonitoring on autonomic nervous system during thyroid surgery.

BACKGROUND: Continuous intraoperative neuromonitoring (CIONM) via vagal nerve stimulation (VNS) is a new option for recurrent laryngeal nerve (RLN) protection during thyroid surgery. The aim of this study was to evaluate the safety of VNS for CIONM and to assess its effects on the autonomic nervous system (ANS) through analyzing heart rate variability (HRV). METHODS: In a prospective, nonrandomized controlled study 5 patients received VNS for CIONM and 5 were operated on with conventional intermittent intraoperative neuromonitoring (IONM). HRV was analyzed in accord with patient-specific reference values. RESULTS: VNS resulted in significantly altered ANS balance. Relative parasympathetic activity increased during VNS. Yet, no relevant cardiac arrhythmias or hemodynamic alterations were observed during VNS. CONCLUSION: HRV analysis revealed a distinct impact of VNS for CIONM on ANS balance. VNS caused parasympathetic predominance that was not countered by increased sympathetic activity.

Microtechnologies in medicine: an overview.

Microsystems technology (MST) has become a significant enabler of novel medical devices and implants over the last years. Typical examples are MST units in cardiac rhythm management devices or in hearing implants. A classification of medical MST applications can be made according to their relationship with the anatomy that is based on the kind and duration of interaction with the human body: Class 1: Extra-corporeal devices such as telemetric health monitoring systems or point of care testing systems. Class 2: Intra-corporeal devices such as intelligent surgical instruments. Class 3: Temporarily incorporated or ingested devices, such as telemetric endoscopes. Class 4: Long-term implantable devices such as telemetric implants. Medical applications of MST are growing at double-digit compounded growth rates, leading to a forecasted global market volume of over USD 1 billion in 2006 or 2007, making MST devices a relevant segment of the medical technology market. The clinical foundation for promoting the use of MST in medicine is mainly based on the significant potential of MST to enable products that improve early disease detection and the monitoring of chronic illnesses. This refers to a number of the most important health problems such as cardiovascular disease, hypertension, diabetes and cancer, to name just a few. More recently microrobotics has become a relevant research area for enabling the atraumatic transport of MST-enhanced diagnostic and therapeutic devices inside the human body.